Backside heating and fixing apparatus in an electronic photograph duplicator

ABSTRACT

Contact fusing apparatus for fixing powder images to a substrate. The apparatus comprises a heated roll or cylinder to which the substrate is electrostatically tacked to improve heat transfer thereto. In order to prevent &#39;&#39;&#39;&#39;trail-end flip up&#39;&#39;&#39;&#39; of the substrate, means are provided to produce an attractive force between the substrate and means for guiding the substrate to the heated roll, but only after the substrate has been tacked to the heated roll.

United States Patent [191 Wako July 8, 1975 [54] BACKSIDE HEATING ANDFIXING 3,174,748 3/1965 Roberts et al. 355/3 APPARATUS 3,29l ,466l2/l966 ASCT Cl 3|. 432/60 PHOTOGRAPH DUPLICATOR 3,309,960 3/1967Delplanque 355/3 3,685,898 8/1972 Gonzalez r 226/94 [75] Inventor; ShojiWako, Atsugi Japan 3,738,855 6/l973 Gundlach 96/l5 D [73] Assignee: RankXerox, Ltd., London, England Primary Examiner-John J. Camby [22] Filed:Nov. 14, 1973 Assistant Examiner-Henry C. Yuen [2|] Appl. N0.: 415,598

[57] ABSTRACT 52 us. Cl. 432/60; 355/3; 226/94 Contact fusing apparatusfor fixing Powder images to a 511 rm. Cl. G03g 15/00; B65h 17/28Sub-Wale- The apparatus cflmprises a healed or 5 Fi l f Search H 432 590 227 22 230 cylinder to which the substrate is electrostatically432/231; 355/3 3' 96/15 250/324 tacked to improve heat transfer thereto.In order to 5 226/94 prevent trail-end flip up" of the substrate, meansare provided to produce an attractive force between the [56] Referencescu substrate and means for guiding the substrate to the UNITED STATESPATENTS heated roll, but only after the substrate has been tacked to theheated roll. 2,573,88! l1/l95l Walkup et a]. 250/325 3,l72,657 3/[965Brandt 226/94 5 Claims, 5 Drawing Figures mm'mJuL 81975 %,8S33,8OO

SHEET 1 BACKGROUND OF THE INVENTION This invention relates, in general,to apparatus for fusing powder images to a substrate; and, moreparticularly, to a contact fuser which softens the powder images bymeans of heat conducted through the back of the substrate.

In the case ofa backside heating and fixing apparatus in anelectrophotographic duplicator. more specifically, in the case of such abackside heating and fixing apparatus that a heating roller withelectric insulating material coated into a thin film on the surface of agrounded electroconductive roller is subjected to electrification by theapplication of a process of corona discharge for the purpose of fixingsuch a thermally plasticized resin material as is supported onduplication paper into an image pattern, i.e., so to speak, a toner, andan electric charge of such polarity as is reversed to that of saidheating roller is applied on the duplication paper supporting the tonerinto an image pattern, the heating roller and the duplication paper arecaused to come in contact with each other by virtue of the electrostaticforce thereof, heat transmission is effected by conduction to thus heatthe duplication paper, and the toner is concurrently welded until thetoner is fixed upon the surface of the duplication paper. the rear endof the duplication paper is prone to pass by without being adapted to,hence without coming in contact with, the heating roller, thus resultingin no fixation at all.

The cause whereof lies in the fact that the section of the duplicationpaper 2 kept in contact with the heating roller 1 gives the saidduplication paper such force as to revolve in the direction the heatingroller 1 is revolving in, which is conjectured to take shape due to therelation between said force and the contact force of the duplicationpaper 2 with the heating roller I as shown in FIG. 1.

Accordingly, it is a primary object of this invention to provide a newand improved apparatus and method of fusing powder images to asubstrate.

It is a more particular object of this invention to provide in a contactfusing device, means for preventing trail-end flip up."

BRIEF DESCRIPTION OF THE INVENTION Briefly, the above-cited objects areaccomplished by providing a contact fuser in the form of a heated rollin combination with means for guiding a substrate into contact therewithwherein the substrate is electrostatically tacked to the heated roll toimprove the fusing process and wherein an attractive force is providedbetween the substrate and the guide means. The attractive force isprovided only after the leading portion of the substrate has beenelectrostatically tacked to the heated roll to thereby insure that thesubstrate can be moved from the guide to the heated roll.

Other objects and advantages will become apparent in view of thedescription of the specification as related to the drawings wherein:

FIGS. 1 and 2 are schematic plan views of a prior art contact fuserwithout the improvements contemplated;

FIG. 3 is a schematic plan view ofa contact fusing device representingthe invention;

FIG. 4,is a modified form of the improvement contemplated; and

FIG. 5 is another modified form of the improvement contemplated.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT Now that, in case thesection of the duplication paper 2 backside heating and fixing apparatusis employed, a concrete description of an illustration of the presentdevice will be given below, by making reference to the drawings,including FIGS. 3-5, attached hereto.

In the drawings, I is a heating roller; 2 is duplication paper; 3 is acorotron for effectuating electrification over said duplication paper 2;4 is a corotron for effectuating electrification over said heatingroller I and is of the reverse polarity to that of said corotron 3; 5 isa stripper for exfoliating the duplication paper 2 off the heatingroller 1, and 6 is a conveying mechanism for the duplication paper 2.

.7 is a guide plate (hereinafter to be termed as a feedin chute) set inplace between the conveying mechanism 6 and the heating roller 1, andthis feed-in chute is set in place on the contact surface of the heatingroller I, so that the duplication paper 2 can be fed into the heatingroller I from the conveying mechanism 6 in a smooth manner.

Shown in FIG. 3 is such a design that a corotron 8 is set in place as ameans of giving proper force for causing the duplication paper 2 to befed in contact with said, feed-in chute 7, to thus cause the duplicationpaper 2 to be properly fed in contact with the feed-in chute 7 by coronadischarge, and in this case. the feedin chute 7 is required to beproperly grounded. Now that, when the corotron 8 is subjected to coronadischarge, starting from the time before the duplication paper 2 is fedinto the feed-in chute 7, the duplication paper 2 might possibly keepstaying in the feed-in chute 7, it is recommendable to subject thecorotron 8 to corona discharge only after the duplication paper 2 iskept in contact with the heating roller 1 to thus have sufficient torquegiven by the heating roller 1, since this proves a requirement forobtaining a desirable result. The corotron 8 simply has to be subjectedto such corona discharge as is sufficient to give the duplication paper2 the minimum level of force required of the duplication paper 2 to runalong the feed-in chute 7.

Shown in FIG. 4 is such a case that an electrostatically charging systemis employed for said feed-in chute 7,, and a desirable result wasobtained when the voltage in such a range as approximately 300 1,000Vwas applied on said feed-in chute.

Shown in FIG. 5 is such a case that an air suction system is employedfor the feed-in chute 7 wherein the duplication paper is caused to befed in such a manner as to come in close contact with the feed-in chute7 and in this case a fairly large quantity of suction air is required;however, the result of an experimentation showed that a desirable effectcould be obtained by the employment of a blower of 5 m lmin.

The backside heating and fixing apparatus introduced in the presentdevice is, at set forth above, furnished with such a flat plate-shapedfeed-in chute as is set in place between the backside heating roller andthe duplication paper conveying mechanism and causes the surface to beoverlapped with the contact surface of the backside heating roller, andfurnished with at least one measure for giving birth to physicalabsorption force between the said backside heating roller and theduplication paper and between the said feed-in chute and the duplicationpaper, respectively, therefore, this backside heating and fixingapparatus proves to be well capable of preventing in a secure mannersuch an unfixed section as is often or sometimes given birth in the rearend section of the duplication paper in case a conventional backsideheating and fixing apparatus is employed.

Since numerous changes may be made in the above described apparatus anddifferent embodiments of the invention may be made without departingfrom the spirit thereof, it is intended that all matter contained in theforegoing description or shown in the accompanying drawings, shall beinterpreted as illustrative and not in a limiting sense.

What is claimed is: l. A method of fusing toner images to a substrateutilizing a heated member and guide means for directing the substrateinto contact with the heated member and further utilizing first meansfor effecting intimate contact between said substrate and said heatedmember and second means for effecting intimate contact between thesubstrate and said guide means, said method comprising the steps of:

moving said substrate into contact with said guide means and said heatedroll, in that order;

energizing said first means for affecting intimate contact between saidsubstrate and said heated roll; and

subsequently energizing said second means for cffecting intimate contactbetween said substrate and said guide means for preventing trail-endflip-up of said substrate.

2. Apparatus for fusing powder images to a substrate, said apparatuscomprising:

a heated roll for contacting the side of said substrate opposite saidpowder images;

means for guiding said substrate into contact with said heated roll;

means for effecting intimate contact between said substrate and saidheated roll once said substrate contacts said heated roll; means forproviding an attractive force between said guide means and saidsubstrate subsequent to the energization of said means for effectingcontact between said substrate and said heated roll; and

means for rendering said attractive force providing means operative onlyafter intimate contact is established between said substrate and saidheated roll.

3. Apparatus according to claim 2 wherein said means for providing anattractive force between said guide means and said substrate comprisesmeans for creating a pressure differential across said substrate.

4. Apparatus according to claim 2, wherein said means for providing anattractive force between said guide means and said substrate comprises asource of electrical potential.

5. Apparatus according to claim 4, wherein said source of electricalpotential comprises a corona discharge device.

1. A method of fusing toner images to a substrate utilizing a heatedmember and guide means for directing the substrate into contact with theheated member and further utilizing first means for effecting intimatecontact between said substrate and said heated member and second meansfor effecting intimate contact between the substrate and said guidemeans, said method comprising the steps of: moving said substrate intocontact with said guide means and said heated roll, in that order;energizing said first means for affecting intimate contact between saidsubstrate and said heated roll; and subsequently energizing said secondmeans for effecting intimate contact between said substrate and saidguide means for preventing trail-end flip-up of said substrate. 2.Apparatus for fusing powder images to a substrate, said apparatuscomprising: a heated roll for contacting the side of said substrateopposite said powder images; means for guiding said substrate intocontact with said heated roll; means for effecting intimate contactbetween said substrate and said heated roll once said substrate contactssaid heated roll; means for providing an attractive force between saidguide means and said substrate subsequent to the energization of saidmeans for effecting contact between said substrate and said heated roll;and means for rendering said attractive force providing means operativeonly after intimate contact is established between said substrate andsaid heated roll.
 3. Apparatus according to claim 2 wherein said meansfor providing an attractive force between said guide means and saidsubstrate comprises means for creating a pressure differential acrosssaid substrate.
 4. Apparatus according to claim 2, wherein said meansfor providing an attractive force between said guide means and saidsubstrate comprises a source of electrical potential.
 5. Apparatusaccording to claim 4, wherein said source of electrical potentialcomprises a corona discharge device.